By Mayor Mary Marvin and the Village Board of Trustees

March 13, 2024: On March 1, 2024, the Village received a letter from Mt. Vernon requesting (1) that the Village “cease and desist” from implementing proposed stormwater drainage improvement plans in Bronxville until those plans could be further evaluated by Mt. Vernon, and (2) that the Village respond to an alleged unaddressed “MS4 violation” relating to the discovery of fecal bacteria in a stormwater drainage line that is used by both Mt. Vernon and Bronxville. 

The Village responded to Mt. Vernon on March 7^th by (a) agreeing to suspend the proposed stormwater drainage plans until both Village and City officials have had a further chance to meet to review stormwater issues that both communities face, and (b) meet with Mt. Vernon officials and staff to analyze and address issues relating to the identification of fecal bacteria in a discharge sample (the “MS4 Contamination Issue”).    

The Village is issuing this statement to update the public on the two matters that Mt. Vernon raised in its March 1 letter and to provide a status report on the Village’s response.  The Village is also issuing this statement to provide relevant context and clarification of certain important facts – including the fact that (contrary to certain erroneous media reports) there has not been an engineering determination that the originating source of the sample contamination was within the Village of Bronxville.  It also bears emphasis that the Village of Bronxville takes very seriously all matters relating to the condition of its stormwater drainage system, its separate sanitary sewage drainage system, and the importance of keeping those two systems physically separate in order to prevent stormwater runoff from being contaminated by contact with any sewage discharges. 

Given the Village’s efforts to continually maintain and upgrade its physically separate stormwater and sewage systems, the Village believes that (i) its proposed Stormwater Drainage Improvement Plans, and (ii) the contamination issue identified in a 2022 sampling, are unrelated.  The Village intends to consult in good faith with our neighbors in Mt. Vernon to confirm this, and trusts that, upon further review, facts and qualified engineering analysis -- rather than rumor and speculation – will be the basis for going forward. 

Background:  Why Have These Issues Arisen Now? 

Beginning in 2021 and continuing into the fall of 2023, the neighborhood in the vicinity of the intersection of Hamilton and Sussex in the south-east part of Bronxville has experienced unprecedented flooding.  Upon review by the Village’s hydraulic engineering consultants, it was determined that this flooding was due to high intensity rain events, which resulted in the existing 1920’s-era stormwater drainage system in this part of the Village being overwhelmed.  In short, the capacity of the 1920’s system has degraded over time and the slope of the pipes was too flat (particularly from the Hamilton/Sussex intersection to the Homesdale/Pine Terrace intersection) to allow the water to drain efficiently to prevent flooding.  It was also determined that certain right-angled joints were improperly installed where the existing stormwater line crosses under Pondfield Road in Bronxville, further impeding efficient drainage.

Accordingly, in the second half of 2023, the Village tasked its hydraulic engineering consultants to develop solutions to this flooding problem.  At all times the Village made clear to its consultants that it wanted solutions that would not simply transfer a flooding problem from one area to another, but that would instead allow stormwater to be more efficiently transferred underground, following the system’s current existing route, to its ultimate discharge point (in this case, the Hunts Woods outfall and stream) that runs through Hunts Woods and thence into the Bronx River. 

The Village’s [Hamilton-Homesdale] Stormwater Improvement Plan

In sum, the resulting Stormwater Improvement Plan – which the Village approved in December, 2023 – calls for (a) restoring adequate capacity to the existing stormwater drainage system by installing new underground stormwater drain pipes along the Hamilton-Homesdale corridor, (b) eliminating the right-angled “zig-zags” underneath Pondfield Road (and replacing them with more efficient “smoothed-curve" piping); (c) installing new underground pipes down Homesdale Road that have longer continuous downward slope (to eliminate the relatively flat slope that currently exists, prior to the relatively sharp drop-off in last few hundred feet of Homesdale between Pine Terrace and Locust Lane).

This Plan – which would follow the course of the existing stormwater drainage pipe network that has existed for over 100 years – would be carried out entirely within Bronxville.  And, consistent with the area’s existing drainage network, the Bronxville section of the existing stormwater drainage system would continue to flow into and connect up with a 36-inch diameter stormwater drain located in the City of Mount Vernon.  That drain – which also collects stormwater run-off from neighboring areas within Mt. Vernon -- runs under Central Parkway and Vernon Parkway (in Mt. Vernon) for approximately 1000 feet before discharging into Hunts Woods at a point (the “Discharge Point”) that is also located in Mt. Vernon. 

It is the Village of Bronxville’s understanding that the capacity of the shared existing 36-inch diameter line under Central Parkway has more than enough capacity to handle any increased temporary flow rates of stormwater from the improved Hamilton-Homesdale line, without causing any increased risk of stormwater flooding (a) anywhere along that line, (b) anywhere along Locust Lane, or (3) anywhere in Mt. Vernon (including along, adjacent to, or near the existing underground 36 inch line that runs under Central Parkway). 

In lower Westchester, communities share stretches of common stormwater drainage pipes, given that – even though all such systems need to eventually drain into local rivers or streams -- municipal boundaries do not often track the lines of nature’s original watersheds and other natural drainage topographies.  Accordingly, just as portions of the Village of Tuckahoe’s stormwater system have fed into and utilized shared stormwater lines located in Bronxville for over a hundred years, so to Bronxville’s stormwater system has fed into and used the Central Parkway stretch of the shared stormwater system located in Mt. Vernon since time immemorial.    

As noted above, however, the Village of Bronxville will consult further with Mt. Vernon to make doubly sure that the more efficient stormwater drainage flows contemplated by the Village’s plans will not have negative consequences for residents of Mt. Vernon.  Indeed, the existing plans contemplate the installation of valves that would prevent precisely such unforeseen circumstances (by limiting the flow of water into Mt. Vernon) just in case – even though the Village’s consulting hydraulic engineers do not believe that such valves would ever need to be activated.  In short, and while respectfully reserving all of its legal rights (as the City of Mt. Vernon has done), the Village looks forward to having further constructive conversations with Mt. Vernon officials about the Village’s plans to implement important stormwater drainage improvements. 

The MS4 Contamination Issue:

Against this backdrop, a 2022 sampling report by Mt. Vernon’s Consulting Engineer registered unacceptably high levels of fecal matter.  It appears that Mt. Vernon officials believe that the discharge point from which the sample at issue was taken is the discharge point at the end of the Central Parkway stormwater drainage line – i.e., the same stormwater drainage line referenced earlier that is connected to both Bronxville’s existing Hamilton-Homesdale line and various lines located wholly in Mt. Vernon. 

Based on the foregoing, Mt. Vernon appears to have concluded that the Village of Bronxville (or property owners in Bronxville) must be responsible for the contamination identified in 2022, rather than Mt. Vernon (or property owners located in Mt. Vernon) -- and that the Village is in violation of its MS4 permit. 

To be clear, the Village of Bronxville is unaware of the Village (or any Village property owner) being confirmed as the originating source of any alleged MS4 violation arising from the 2022 sample that was apparently taken in Mt. Vernon.  Indeed, the Village was surprised to read of this allegation in Mt. Vernon’s March 1 letter given that -- despite the Village’s regular communications with Mt. Vernon’s Department of Public Works (“DPW”) officials in 2022, 2023 and even as recently as early 2024 – such allegations had not previously been raised with Village officials. 

For example, as recently as November 2023, the Village Administrator reached out to Mt. Vernon officials to specifically inquire about how the Village of Bronxville and the City of Mt. Vernon might be able to work together to obtain federal or state funding to insure the physical integrity of the Laurel Brook/Hunts Woods Channel (including anti-erosion protections), given the vital role of this channel in providing stormwater drainage to both communities.  Even earlier in 2023, the Village was also in communication with Mt. Vernon officials regarding (1) the Village’s planned sanitary sewer system improvements along Wood End Lane (which clearly benefitted the Laurel Brook area, at Village expense, by allowing the removal of several residential septic systems located on that street), and (2) stormwater drainage improvements on Locust – two projects also located very near the Homesdale-Central Parkway drainage line and Laural Brook area – yet there was again no mention by Mt. Vernon officials of the 2022 sample, nor any suggestion that Bronxville (rather than Mt. Vernon) was the originating source for any contamination findings.  

The Village has devoted substantial resources to regularly inspecting and maintaining both its stormwater drainage system (MS4) and its separate sanitary sewer system.  Given the Village’s record in this regard, the Village believes that any allegations that Bronxville is the source of the contamination found in the single sample that was collected in Mt. Vernon in 2022 are unsubstantiated. [1] 

Nonetheless, the Village welcomes the opportunity to work collectively with our Mt. Vernon neighbors – as we have done with all of our other abutting municipal neighbors in Yonkers, Eastchester and Tuckahoe -- to identify and eliminate the discharge of any sewage or other contaminated materials into any portions of our mutually interconnected stormwater drainage systems (including the Bronx River and its tributaries).  Such efforts necessarily require time, effort and appropriate funding.  But solutions require constructive action and cooperation, which the Village believe is best facilitated by developing the relevant facts, rather than by reaching unconfirmed conclusions based on a two year old sample(s). 

As confirmation of the Village’s commitment to working in good faith with our neighbors in Mt. Vernon, the Village also notes that last week it reached out to Mt. Vernon officials to explore ways that our two communities might undertake coordinated efforts to identify any possible sources of sewage or other contaminated discharge.  Such efforts already included inspecting and cleaning the City of Mt. Vernon sanitary sewer line that runs adjacent to the stormwater line in the area from which the 2022 sample was apparently taken.  Further testing may also be appropriate. 

The Path Forward

The Village will continue to communicate with relevant Mt. Vernon officials, and the Village looks forward to Mt. Vernon officials doing the same with relevant Village officials.  We are highly confident that, upon further review, it will become clear that Bronxville’s implementation (at its own expense) of its Proposed Stormwater Drainage Plan is a significant step towards improving certain stormwater drainage problems that will not have any adverse impacts on our neighbors in Mt. Vernon.  And, based on what we presently know, we are also confident that, after further review, the “MS4 Contamination Issue” provides no basis for impeding Bronxville’s planned drainage improvements.

[1]  More specifically, the Village has spent over $5 million in recent years on (A) mapping, televising, cleaning, repairing, replacing, and lining our sanitary sewers over the past decade and (B) mapping, televising, cleaning, repairing and upgrading the Village’s stormwater drainage system.  Indeed, the Village’s commitment to maintaining the highest quality sanitary sewage system is further confirmed by its work in drafting a proposed local law (currently the subject of public hearings) that would require Bronxville property owners to have their sanitary sewer lateral lines inspected to help ensure that those lines are not exfiltrating into the Village’s stormwater drainage system – which would make Bronxville one of only a handful of other Westchester municipalities to impose such a requirement.  And while also working to improve the efficiency of the Village’s 100+ year-old stormwater drainage system, the Village has been proactive in taking other steps to reduce the amount of stormwater run-off in the first place by, for example, enacting several zoning law changes that limit residents' ability to increase the amount of impermeable surface area on their property (so that more water is absorbed into the ground without ever entering the stormwater drainage system).